The Effect of Grinding Conditions on Lead Zirconate Titanate Machinability

In many of the existing and newly emerging applications for ferroelectrics there is a need to machine them to high precision, with control over the surface and near surface properties. This is particularly the case regarding microdevices. With such devices, cracking and ferroelastic domain reorientation can result in significant degradation in device performance due to grain pullout, strength degradation and depoling of the near surface region. It is vital that the parameters controlling machinability are determined and their effects characterised. From such information, optimum machining conditions may then be selected. The effects of fixed abrasive dicing conditions have been studied in four lead zirconate titanate compositions suitable for piezoelectric actuator applications. The severity of brittle surface damage has been investigated by image analysis. The thicknesses of the depoled regions have been measured by their effects on the piezoelectric coupling factors of array elements of various widths. It has been established that machinability is particularly sensitive to wheel grit size, feed rate and material composition.